Display device

ABSTRACT

A display device includes: a first insulating substrate; a main pixel which is formed on the first insulating substrate and comprises a plurality of sub-pixels and a single sensing electrode; a second insulating substrate which faces the first insulating substrate; a sensing spacer formed on the second insulating substrate which faces the sensing electrode; and a contact electrode formed on the sensing spacer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional Patent Application of U.S. patentapplication Ser. No. 11/940,070, filed on Nov. 14, 2007, whichapplication claims priority from Korean Patent Application No.10-2006-0135214, filed on Dec. 27, 2006 in the Korean IntellectualProperty Office, the disclosures of each of which are incorporatedherein by reference in their entireties.

BACKGROUND OF INVENTION

1. Field of Invention

Apparatuses and methods consistent with the present invention relate toa display device, more particularly, to a display device which has aninner type touch panel.

2. Description of the Related Art

A touch panel, generally provided at the uppermost surface of a display,accepts user input by means of the touch of a finger tip or object toselect contents displayed on the screen of the display device. A displaydevice, such as a liquid crystal display, having a touch panel does notneed input components such as a keyboard, a mouse, etc.

Some displays use an internal pressure-sensor to sense an externalcontact. A spacer and two or three sensing electrodes are formed insidethe display adjacent to a specific pixel to transmit positioninformation. Accordingly, the pixel where the sensing electrodes areformed has a decreased aperture ratio and the rendition of red, green,and blue colors may become unbalanced. Further, pressure may be detectedby the sensing electrodes at two or more points and thus the positioninformation may not be properly transmitted if sensing electrodes havedifferent heights.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide apressure-sensing display device having an improved aperture ratio andvisibility.

Another aspect of the present invention is to provide a display devicewhich obtains position information easily and accurately.

The foregoing and/or other aspects of the present invention can beachieved by providing a display device comprising: a first insulatingsubstrate; a main pixel which is formed on the first insulatingsubstrate and which has a plurality of sub-pixels and a single sensingelectrode; a second insulating substrate which faces the firstinsulating substrate; a sensing spacer formed on the second insulatingsubstrate which faces the sensing electrode; and a contact electrodeformed on the sensing spacer.

According to an aspect of the invention, each sub-pixel comprises: agate line; a data line which intersects the gate line; a thin filmtransistor formed at an intersection area of the gate line and the dataline; and a pixel electrode electrically connected to the thin filmtransistor, wherein the main pixel comprises a red sub-pixel, a greensub-pixel and a blue sub-pixel.

According to an aspect of the invention, the display device furthercomprises: a first sensing line formed parallel with the gate line; asecond sensing line formed parallel with the data line; and an extendingpart which extends from the second sensing line and overlaps with thesensing electrode.

According to an aspect of the invention, the main pixel comprises: afirst main pixel which comprises a Y-sensing electrode connected to thefirst sensing line; and a second main pixel which comprises an X-sensingelectrode connected to the second sensing line, wherein the first mainpixel and the second main pixel are disposed alternately.

According to an aspect of the invention, the pixel electrode in eachsub-pixel has substantially the same area.

According to an aspect of the invention, a pixel electrode of onesub-pixel is smaller in area than those of the other sub-pixels becauseof the sensing electrode.

According to an aspect of the invention, a pixel electrode of the bluesub-pixel is smaller in area than those of the other sub-pixels becauseof the sensing electrode.

According to an aspect of the invention, the sensing electrode is formedin the same layer as the pixel electrode.

According to an aspect of the invention, the display device furthercomprises a common electrode formed on the second insulating substrate,wherein the common electrode and the contact electrode are supplied witha predetermined level of common voltage.

According to an aspect of the invention, the contact electrode is formedin the same layer as the common electrode.

According to an aspect of the invention, the contact electrode is formedin a different layer from the common electrode.

According to an aspect of the invention, the display device furthercomprises a cell gap spacer formed on the second insulating substrate.

The foregoing and/or other aspects of the present invention can beachieved by providing a display device comprising: a first insulatingsubstrate; a gate line and a data line which are formed on the firstinsulating substrate and intersect each other; a Y-sensing line formedparallel with the gate line; an X-sensing line formed parallel with thedata line; a first pixel which is connected to the Y-sensing line andcomprises a Y-sensing electrode which generates a Y position signalreacting to an external stimulus; a second pixel which is connected tothe X-sensing line and comprises an X-sensing electrode which generatesan X position signal reacting to the external stimulus; and a sensingdriver which receives the Y position signal from the first pixel and theX position signal from the second pixel among position informationreacting to the external stimulus.

According to an aspect of the invention, the first pixel and the secondpixel are disposed alternately.

According to an aspect of the invention, the first pixel and the secondpixel comprise: at least one thin film transistor formed at anintersection area of the gate line and the data line; and a pixelelectrode connected to the thin film transistor.

According to an aspect of the invention, the first pixel and the secondpixel comprise a red sub-pixel, a blue sub-pixel and a green sub-pixel,and the pixel electrode in each sub-pixel has substantially the samearea.

According to an aspect of the invention, the first pixel and the secondpixel comprise a red sub-pixel, a blue sub-pixel and a green sub-pixel,and a pixel electrode of the blue sub-pixel is smaller in area thanthose of the other sub-pixels because of the Y-sensing electrode or theX-sensing electrode.

According to an aspect of the invention, the display device furthercomprises: a second insulating substrate which faces the firstinsulating substrate; a sensing spacer formed on the second insulatingsubstrate which faces the Y-sensing electrode and the X-sensingelectrode; a contact electrode formed on the sensing spacer; and acommon electrode formed on the second insulating substrate.

According to an aspect of the invention, the common electrode and thecontact electrode are applied with a common voltage of a predeterminedlevel.

According to an aspect of the invention, the contact electrode faces theX-sensing electrode and the Y-sensing electrode.

According to an aspect of the invention, areas of the Y-sensingelectrode and the X-sensing electrode are the same as or lager than anarea of the contact electrode.

According to an aspect of the invention, the contact electrode is formedin the same layer as the common electrode.

According to an aspect of the invention, the contact electrode is formedin a different layer from the common electrode.

According to an aspect of the invention, the display device furthercomprises a cell gap spacer formed on the second insulating substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects of the present invention will becomeapparent and more readily appreciated from the following description ofthe exemplary embodiments, taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a control block diagram of a display device according to afirst exemplary embodiment of the present invention;

FIG. 2 is a plan view of the display device according to the firstexemplary embodiment of the present invention;

FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2;

FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2; and

FIG. 5 is a plan view of a display device according to a secondexemplary embodiment of the present invention.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to like elementsthroughout. The exemplary embodiments are described below so as toexplain the present invention by referring to the figures.

Referring to FIG. 1, a display device according to a first exemplaryembodiment of the present invention has a touch-screen function whichdisplays images formed according to an external pressure. The displaydevice includes a sensing electrode S.E to sense pressure disposed in adisplay panel 100 in an inner type.

The display device according to the present exemplary embodimentincludes the display panel 100, a gate driver 210, a data driver 220 anda sensing driver 230 to process a sensing signal. The display panel 100is provided as a liquid crystal display panel (see FIG. 3) whichincludes a liquid crystal layer.

The display panel 100 includes a plurality of main pixels, and each mainpixel includes a red sub-pixel, a blue sub-pixel and a green sub-pixel(see FIG. 2). A main pixel includes a sensing electrode S.E, and eachsub-pixel includes at least one thin film transistor (TFT) T. Thedisplay panel 100 includes a gate line G.L which extends in apredetermined direction and a data line D.L which intersects the gateline G.L in order to apply signals to the TFT. Further, the displaypanel 100 includes a Y sensing line Y-S.L which extends parallel withthe gate line G.L and an X sensing line X-S.L which extends parallelwith the data line D.L in order to transmit predetermined electricsignals from the sensing electrode S.E.

The main pixel includes a liquid crystal capacity CI between the TFT Tand a common voltage (Vcom) and a storage capacity Cst connected to theTFT T. When a gate on signal is applied to the gate line G.L to turn onthe TFT T, a data voltage Vd supplied to the data line D.L is applied toa pixel electrode (not shown) through the TFT T.

The electric field difference between the pixel voltage Vp applied tothe pixel electrode and the common voltage Vcom is generated in liquidcrystals (illustrated as a liquid crystal capacitance CI in FIG. 1).Light is transmitted through the liquid crystal corresponding to theintensity of the electric field which varies the transmittance of theliquid crystal. The pixel voltage Vp should be maintained for one frame,and the auxiliary storage capacitor Cst is used to maintain the pixelvoltage Vp applied to the pixel electrode.

The sensing electrode S.E in the main pixel transmits an electric signalthat reacts to an external stimulus such as pressure to the sensing lineS.L. The sensing electrode S.E includes a Y-sensing electrode Y-S.Ewhich is connected to the Y-sensing line Y-S.L to transmit Y positioninformation and an X-sensing electrode X-S.E which is connected to the Xsensing line X-S.L to transmit X position information. In the displaydevice according to the present embodiment, a main pixel includes onesensing electrode S.E, which is a one-point contact type.

In a conventional display device, the use of two or more sensingelectrodes to sense position information in a main pixel, especially inone sub-pixel, cause the sub-pixels to be asymmetric, thereby reducingvisibility. Further, when two or more sensing electrodes are provided,and all must be stimulated simultaneously generate position information.If one of the sensing electrodes is not stimulated, position informationis not transmitted. Further, if the sensing electrodes have differentheights, stimulus may not properly be given to the sensing electrodes.

In the present exemplary embodiment, the Y-sensing electrode Y-S.E tosense Y position information and the X-sensing electrode X-S.E to senseX position information are not formed in the same main pixel but areformed in different main pixels. If the main pixels provided with theY-sensing electrode Y-S.E and the X-sensing electrode X-S.E are referredto as a first main pixel and a second main pixel respectively, the firstmain pixel and the second main pixel are disposed uniformly andalternately in the display panel 100. As the size of the main pixel isconsiderably smaller compared to the external stimulus, the sensingelectrodes S.E may sufficiently react to the external stimulus althoughnot being formed in the same main pixel. The sensing electrode S.E maybe provided in each main pixel or the sensing electrode S.E may beformed at a predetermined interval.

The sensing driver 230 receives X position information pertaining to astimulus through the second main pixel and Y position informationpertaining thereto through the first main pixel, and controls the imageapplied to the display panel 100 using the received positioninformation. The sensing driver 230 may include an analog-digitalconverter (not shown) which processes electric signals transmitted fromthe sensing line S.L.

The gate driver 210, also referred to as a scan driver, is connected tothe gate line G.L to apply a gate signal which consists of a combinationof a gate-on voltage Von and a gate-off voltage Voff.

The data driver 220 is also referred to as a source driver. The datadriver 220 is supplied with a gray scale voltage from gray scalevoltages generating part (not shown), selects a gray scale voltageaccording to external control, and applies a data voltage to the dataline D.L.

Referring to FIGS. 2 to 4, the sensing electrode according to thepresent exemplary embodiment will be described in detail. The displaydevice according to the present exemplary embodiment includes a firstsubstrate 300 where the main pixels I and II are formed, a secondsubstrate 400 to face the first substrate 300 and a liquid crystal layer500 disposed between the substrates 300 and 400.

The main pixels I and II are arranged in a matrix form on the firstsubstrate 300. Each main pixel I and II includes the red sub-pixel R,the green sub-pixel G, the blue sub-pixel B and one sensing electrode372 and 373. The sub-pixels R, G and B are generally rectangular-shaped.The main pixels I and II include the first main pixel I which includesthe Y-sensing electrode 372 and the second main pixel II which includesthe X-sensing electrode 373. The first main pixel I and the second mainpixel II are disposed adjacent to each other. That is, the first mainpixel I and the second main pixel II are disposed alternately, and onefirst main pixel I is surrounded by the second main pixels II.

In the present exemplary embodiment, as the sensing electrodes 372 and373 are formed in the blue sub-pixel B, the blue sub-pixel B has asmaller area than the red sub-pixel R and the green sub-pixel G. Each ofthe sub-pixels R, G and B includes a TFT and a pixel electrode 371electrically connected to the TFT.

Alternatively, the first main pixel I and the second main pixel II maybe arranged alternately but spaced at a predetermined interval. Namely,a pixel which does not include the sensing electrode 372 and 373 isfurther provided between the first main pixel I and the second mainpixel II.

In detail, gate wiring is formed on a first insulating substrate 310.The gate wiring may be a metal single layer or metal multi-layers. Thegate wiring includes a gate line 320 extending transversely, a gateelectrode 321 extending from the gate line 320 and a Y-sensing line 323formed parallel with the gate line 320. The gate wiring may furtherinclude a storage electrode line which overlaps the pixel electrode 371to form a storage capacity.

The gate line 320 and the Y-sensing line 323 are formed parallel witheach other. Alternatively, the gate line 320 and the Y-sensing line 323may be formed in zigzags or not parallel with each other.

The Y-sensing line 323 functions as a passage for analog signals such asan electric current or a voltage from the Y-sensing electrode 372 andprovides position information about a pressurized place to the sensingdriver 230 when an upper part of the Y-sensing electrode 372 ispressurized.

A gate insulating layer 330 made of silicon nitride (SiNx) or the likeis formed on the first insulating substrate 310 and covers the gatewiring 320, 321 and 323.

A semiconductor layer 341 is made of amorphous silicon or the like andformed on the gate insulating layer 330 over the gate electrode 321. Anohmic contact layer 342 is made of n+ hydrogenated amorphous siliconwhich is highly doped with silicide or n-type impurities and formed onthe semiconductor layer 341.

Data wiring is formed on the ohmic contact layer 342 and the gateinsulating layer 330. The data wiring may be a single layer ormulti-layer metal. The data wiring includes a data line 350 formedlengthwise to intersect the gate line 320 to form a pixel. An X-sensingline 353 is formed parallel with a source electrode 351. A drainelectrode 352 and data line 350 intersects the Y-sensing line 323, andan extending part 354 formed where the Y-sensing electrode 372 and theX-sensing electrode 373 are to be provided.

The source electrode 351 is branched from the data line 350, and thedrain electrode 352 is connected to the pixel electrode 371 through acontact hole 10.

The X-sensing line 353 functions as a passage where electric signalsgenerated in the X-sensing electrode 373 are transmitted and providesposition information about a pressurized place to the sensing driver 230when the X-sensing electrode 373 is pressurized.

The extending part 354 extends from the X-sensing line 353 and isdisposed under the sensing electrodes 372 and 373. The extending part354 disposed below the Y-sensing electrode 372 maintains an intervalbetween the Y-sensing electrode 372 and a contact electrode 461 of thesecond substrate 400 and an interval between the X-sensing electrode 373and the contact electrode 461 equally (see FIG. 3). If the intervalbetween the Y-sensing electrode 372 and the contact electrode 461 of thesecond substrate 400 and the interval between the X-sensing electrode373 and the contact electrode 461 are maintained uniformly, the sensingelectrodes 372 and 373 have the same height. Thus, the sensingelectrodes 372 and 373 are improved in reactivity to a pressure whenbeing pressurized with a predetermined pressure at the same time. Asensing spacer 451 is provided on the Y sensing electrode 372 where theextending part 354 is formed.

As the Y-sensing electrode 372 is connected to the Y-sensing line 323through a contact hole 20, the extending part 354 formed below theY-sensing electrode 372 may be omitted.

Referring to FIG. 4, the extending part 354 disposed below the X-sensingelectrode 373 is in contact with the X-sensing electrode 373 through acontact hole 30 and transmits an electric signal generated in theX-sensing electrode 373 to the X-sensing line 353.

The extending part 354 is formed in a pixel region where the bluesub-pixel B is disposed, and thus the blue sub-pixel B has relativelysmall an aperture area as compared with the red and the green sub-pixelsR and G. Blue is lower than red or green in visible sensitivity. Thus,when an aperture ratio of the blue sub-pixel B is lower than those ofthe other sub-pixels R and G, a user does not recognize that the bluesub-pixel B is insufficient. Thus, if one of sub-pixels R, G and B isreduced in aperture ratio as the sensing electrodes 372 and 373 areformed, the sensing electrodes 372 and 373 are formed in a pixel regionwhere the blue sub-pixel B is formed to maintain aperture ratios of theother pixels R and G.

A passivation layer 360 is formed on the data wiring and a portion ofthe semiconductor layer 341 which is not covered therewith. The contactholes 10, 20 and 30 are formed in the passivation layer 360 to exposethe drain electrode 352, the Y-sensing line 323 and the extending part354, respectively.

The pixel electrode 371, the Y-sensing electrode 372 and the X-sensingelectrode 373 are formed on the passivation layer 360. The pixelelectrode 371 is made of a transparent conductive material such asindium tin oxide (ITO) or indium zinc oxide (IZO). The sensingelectrodes 372 and 373 are formed of a transparent conductive materialin the same layer as the pixel electrode 371. The blue sub-pixel B has asmaller area than the other sub-pixels R and G due to the sensingelectrodes 372 and 373.

When a stimulus is given from the outside, the contact electrode 461becomes in contact with the Y-sensing electrode 372 and the X-sensingelectrode 373. The Y-sensing electrode 372 and the X-sensing electrode373 may have an enough area to be easily in contact with the contactelectrode 461. Areas of the Y-sensing electrode 372 and the X-sensingelectrode 373 are at least equal to or larger than that of the contactelectrode 461. Further, the areas of the Y-sensing electrode 372 and theX-sensing electrode 373 may be large in such a range as they do notinfluence the aperture ratios.

The Y-sensing electrode 372 and the X-sensing electrode 373 may havedifferent areas or the same area. An area ratio of the Y-sensingelectrode 372 and the X-sensing electrode 372 may be variable dependingon the areas of the contact electrode 461 and the pixel electrode 371.

Next, the second substrate 400 will be described in the following.

A black matrix 420 is formed on a second insulating substrate 410. Theblack matrix 420 is disposed between a red, green and blue filters todivide the filters, and prevents light from being irradiated directly tothe TFT T disposed on the first substrate 300. The black matrix 420 istypically made of a photoresist organic material including a blackpigment. The black pigment may be carbon black, titanium oxide or thelike. Further, the black matrix 420 may include a metal material such aschrome oxide.

A color filter layer 431 is formed on the second insulating substrate410 where the pixel electrode 371 is disposed. The color filter layer431 includes a red, a green and a blue filters which are alternatelydisposed and separated by the black matrix 420. The color filter layer431 endows colors to light irradiated from the backlight unit (notshown) and passing through the liquid crystal layer 500. The colorfilter layer 431 is generally made of a photoresist organic material.The color filter layer 431 may be formed on the first substrate 300 orbe omitted depending on a driving method of the backlight unit.

An overcoat layer 440 is formed on the color filter 431 and the blackmatrix 420 which does not cover the color filter 431. The overcoat layer440 provides a flat surface and protects the color filter layer 431. Theovercoat layer 440 is made of an acrylic epoxy material.

The sensing spacer 451 and a cell gap spacer 452 are formed on theovercoat layer 440 to transmit a sensing stimulus and to form a cellgap, respectively. The sensing spacer 451 is formed over the sensingelectrodes 372 and 373, and the cell gap spacer 452 is formed over theTFT T. The cell gap spacer 452 is provided to keep the first substrate300 spaced from the second substrate 400 at a regular distance. Theliquid crystals are injected to a space formed by the substrates 300 and400. When the user gives a stimulus to an upper part of the secondsubstrate 400, the sensing spacer 451 transmits the stimulus to thefirst substrate 300.

A common electrode 460 is formed on the overcoat layer 440, and thecontact electrode 461 is formed on the sensing spacer 451. The commonelectrode 460 and the contact electrode 461 are formed in the same layerand supplied with a predetermined level of common voltage. The commonelectrode 460 is made of a transparent conductive material such as ITOor IZO. The common electrode 460 and the contact electrode 461 areformed in the same layer by one process where a conductive material isdeposited across the second insulating substrate 410 and the conductivematerial of the upper part of the cell gap spacer 452 is removed. Thecommon electrode 451 applies a voltage directly to the liquid crystallayer 500 along with the pixel electrode 371 of the first substrate 300.

When a stimulus is given to the sensing electrodes 372 and 373 from theoutside, the contact electrode 461 supplied with a common voltage comesin contact with the sensing electrodes 372 and 373 and the commonvoltage is applied to the sensing driver 230 through the sensingelectrodes 372 and 373 and the sensing lines 323 and 353. The sensingdriver 230 detects which of the main pixels I and II transmits theelectric signal to determine the position that has been given thestimulus from the outside. The contact electrode 461 may be provided ina center area of the Y-sensing electrode 372 and the X-sensing electrode373 in order to easily contact with the Y-sensing electrode 372 or theX-sensing electrode 373.

Alternatively, the sensing spacer 451 and the cell gap spacer 452 may beprovided on the common electrode 460. Namely, the common electrode 460and the contact electrode 461 may be formed by separate processes indifferent layers.

The liquid crystal layer 500 which includes liquid crystal molecules isdisposed between the first substrate 300 and the second substrate 400.

FIG. 5 is a plan view of a display device according to a secondexemplary embodiment of the present invention.

Each of sub-pixels R, G and B according to the present embodimentincludes a pixel electrode 374 with substantially the same area. AY-sensing line 323 is spaced from a gate line 320 and traverses a pixelregion where the sub-pixels R, G, and B are formed. A drain electrode352 of a TFT and an extending part 354 are formed under the Y-sensingline 323.

In the present embodiment, as the pixel electrodes 374 of a redsub-pixel R and a green sub-pixel G where the extending part 354 is notformed has the same shape as that of a blue sub-pixel B, an apertureratio and transmittance are uniform in the sub-pixels R, G and B.Accordingly, a kickback voltage difference which may be generated bydifferent sizes of the pixel electrodes 374 of the sub-pixels R, G and Bcan be reduced and an electric property among the sub-pixel electrodesR, G and B becomes uniform.

The sub-pixel electrodes R, G and B have the pixel electrodes 374 withthe same size, and thus the extending part 354 may be provided in one ofregions of the sub-pixels R, G and B.

According to the present invention, as one sensing electrode is formedin each main pixel, the aperture ratio is improved and a specific pixelelectrode is prevented from decreasing in area as compared with aconventional two- or three-point contact type. Further, the positioninformation about the external stimulus is easily transmitted by theone-point contact type, and thus the location where the stimulus isgenerated may be determined more accurately.

As described above, the present invention provides a display devicewhere the aperture ratio is increased and visibility is improved.

Further, the present invention provides a display device which obtainsposition information easily and accurately.

Although a few exemplary embodiments of the present invention have beenshown and described, it will be appreciated by those skilled in the artthat changes may be made in these exemplary embodiments withoutdeparting from the principles and spirit of the invention, the scope ofwhich is defined in the appended claims and their equivalents.

1.-12. (canceled)
 13. A display device comprising: a first insulatingsubstrate; a gate line and a data line formed on the first insulatingsubstrate; a Y-sensing line formed parallel with the gate line; anX-sensing line formed parallel with the data line; a first pixelconnected to the Y-sensing line having a Y-sensing electrode whichgenerates a Y position signal reacting to an external stimulus; a secondpixel which is connected to the X-sensing line having an X-sensingelectrode which generates an X position signal reacting to the externalstimulus; and a sensing driver which receives the Y position signal fromthe first pixel and the X position signal from the second pixel.
 14. Thedisplay device according to claim 13, wherein the first pixel and thesecond pixel are disposed alternately.
 15. The display device accordingto claim 13, wherein the first pixel and the second pixel comprise: atleast one thin film transistor connected to the gate line and the dataline; and a pixel electrode connected to the thin film transistor. 16.The display device according to claim 15, wherein the first pixel andthe second pixel comprise a red sub-pixel, a blue sub-pixel and a greensub-pixel, and the pixel electrode in each sub-pixel has substantiallythe same area.
 17. The display device according to claim 15, wherein thefirst pixel and the second pixel comprise a red sub-pixel, a bluesub-pixel and a green sub-pixel, and a pixel electrode of the bluesub-pixel is smaller in area than those of the other sub-pixels becauseof the Y-sensing electrode or the X-sensing electrode.
 18. The displaydevice according to claim 13, further comprising: a second insulatingsubstrate which faces the first insulating substrate; a sensing spacerformed on the second insulating substrate which faces the Y-sensingelectrode and the X-sensing electrode; a contact electrode formed on thesensing spacer; and a common electrode formed on the second insulatingsubstrate.
 19. The display device according to claim 18, wherein thecommon electrode and the contact electrode are supplied with a commonvoltage of a predetermined level.
 20. The display device according toclaim 19, wherein the contact electrode faces the X-sensing electrodeand the Y-sensing electrode.
 21. The display device according to claim18, wherein areas of the Y-sensing electrode and the X-sensing electrodeare the same as, or lager than an area of the contact electrode.
 22. Thedisplay device according to claim 19, wherein the contact electrode isformed in the same layer as the common electrode.
 23. The display deviceaccording to claim 19, wherein the contact electrode is formed in adifferent layer from the common electrode.
 24. The display deviceaccording to claim 18, further comprising a cell gap spacer formed onthe second insulating substrate.